My problem was originally posted as cel code 15 but now it's a 5.
I replaced a connector for the positive wire coming from the ignitor and taped up a couple of the wires since they were frayed. I put it all back together, reset the ecu, and the same problem was happening.

It was still cold-idling at 1,000 really roughly like it was misfiring then shot up to 2,500rpm then died.

BUT this time instead of 15 the CEL code was 5 which is MAP sensor. WTF?!?! This car is driving me nuts.

Any ideas?

Here's my setup:
'89 CRX dx
'99 d16y8 vtec motor
'89 Integra ecu
Field's vtec controller

 

I had a similar problem (the idle RPM jumping around) when I did my B16A1 swap, but I wasn't getting engine codes...it turned out we didn't have the vaccume plugged up correctly (the B16a1 has some extra vaccume lines and stuff that you don't need when you put it in a 95 ex) but we got those plugged off correctly and everything worked fine.

 

It was a torn vacuum line! Thanks for the suggestion.